A novel hepatitis B virus mutant coexisting with wild type virus in a carrier with negative HBsAg yet positive HBeAg and anti-HBs

Reactivation of Occult Hepatitis B Virus Infection During Long-Term Entecavir Antiviral Therapy

Up to now, it has not been clear whether occult hepatitis B virus (HBV) infection (OBI) can be treated with antiviral therapy whether OBI can develop drug resistance gene mutation or not. We report a middle-aged female patient with OBI who showed HBV reactivation (HBVr) during more than 3 years of intermittent entecavir (ETV) antiviral therapy: seropositive HBV surface antigen (HBsAg), increased e antigen (HBeAg), and repeatedly elevated serum HBV DNA. Genotype analysis showed that the patient was infected with HBV type B. Genetic sequencing of HBV showed the mutants of S143T, D144G, and G145R in the S gene region, and the mutant of site 1896 in the pre-Core region coexisted with the wild type (G1896A/G). No mutation was found in other HBV gene segments. Drug resistance gene analysis found RtL229W mutant, resistant to lamivudine but sensitive to ETV and other nucleoside analogs. This case of OBI provides us with the following clinical experiences: Firstly, it is necessary to detect HBV genotype, mutation, and drug-resistant genes at the initial diagnosis, which can be helpful for reasonable treatment. Secondly, identifying the risk factors and mechanisms associated with HBVr could help quantify the risk of HBVr and manage the clinical consequences. Thirdly, the OBI patients with hepatitis B e antigen-positive, HBV DNA > 1 × 103 IU/ml should be recommended regular and continuous antiviral therapy as soon as possible to prevent the occurrence of hepatocirrhosis and hepatocellular carcinoma (HCC).

Increased protection of earlier use of immunoprophylaxis in preventing perinatal transmission of hepatitis B virus

BACKGROUND

Passive-active immunoprophylaxis against mother-to-child transmission (MTCT) of hepatitis B virus (HBV) recommends administer hepatitis B immunoglobulin (HBIG) and birth dose hepatitis B vaccine in infants within 12 or 24 hours after birth. With this protocol, MTCT of HBV still occurs in 5-10% infants of HBV-infected mothers with positive hepatitis B e antigen (HBeAg).

METHODS

The present study aimed to investigate whether earlier administration of HBIG and hepatitis B vaccine after birth can further increase the protection efficacy.

RESULTS

Totally, 1140 HBV-infected pregnant women were enrolled, and 982 infants (9 twins) of 973 mothers were finally followed up at 9.6 ± 1.9 months age. HBIG and birth dose vaccine were administered in newborn infants with a median 0.17 hour (0.02-1.0) after birth. The overall rate of MTCT was 0.9% (9/982), with none (0%) of 607 infants of HBeAg-negative mothers and 9 (2.4%) of 375 infants of HBeAg-positive mothers. All nine HBV-infected infants were born to mothers with HBV DNA >2.75×106 IU/ml. Maternal HBV DNA levels >1×106 IU/ml was an independent risk factor (OR = 10.627, 95% CI: 2.135-+∞) for immunoprophylaxis failure.

CONSLUSIONS

Earlier use (within one hour after birth) of HBIG and hepatitis B vaccine can provide better protection efficacy against MTCT of HBV.

Occurrence of occult hepatitis B virus infection associated with envelope protein mutations according to anti-HBs carriage in blood donors

OBJECTIVES

Occult hepatitis B virus infection (OBI) carries a risk of hepatitis B virus (HBV) transmission and hepatocellular carcinoma. As previous studies have had a limited sample size, the characteristics of OBI with genotype B and C (OBI_B and OBI_C) mutations relating to hepatitis B surface antibody (anti-HBs) elicited by vaccination or a limited host immune response to HBV have not been fully explored.

METHODS

In this study, the occurrence of OBI_B or OBI_C strains associated with envelope protein (pre-S/S) amino acid substitutions obtained from 99 blood donors stratified according to anti-HBs carriage were characterized extensively.

RESULTS

According to the presence of anti-HBs within each genotype, the number and frequency of substitution sites specific for anti-HBs(-) OBI_B were higher than those specific for anti-HBs(+) OBI_B strains (67 vs 31; 117 vs 41), but the reverse pattern was found in OBI_C strains (3 vs 24; 3 vs 26). Mutations pre-s₁T68I and sQ129R/L were found uniquely in 15-25% of anti-HBs(+) OBI_B carriers and mutation pre-s₁A54E was found preferentially in anti-HBs(+) OBI_C, while 17 substitutions were found preferentially in 11-38% of anti-HBs(-) OBI_B strains. In the major hydrophilic region (MHR) region, mutations sS167 in OBI_B, sT118 in OBI_C, and sA166 in both genotypes were possibly immune-induced escape mutation sites.

CONCLUSIONS

Several mutations in pre-S/S of OBI appeared to be associated with carrier anti-HBs pressure, which might be risk factors for potential reactivation of viruses under anti-HBs selection in OBI carriers.

Safety and efficacy of telbivudine in late pregnancy to prevent mother-to-child transmission of hepatitis B virus: A multicenter prospective cohort study

Infection of hepatitis B virus (HBV) occurs in ~10% of infants of HBV-infected mothers with positive hepatitis B e antigen (HBeAg) after immunoprophylaxis. We aimed to evaluate the safety and efficacy of telbivudine used during late pregnancy for preventing mother-to-child transmission of HBV. We conducted a multicenter prospective cohort study in 5 hospitals from 2012 to 2014, which enrolled HBV-infected singleton pregnant women with positive HBeAg. By their choice, women were divided into therapy (telbivudine 600 mg/day, from gestation 28-32 weeks to 3-4 weeks postpartum) and control (no antiviral agent) groups. Infants received passive-active immunoprophylaxis and follow-up at the age of 7-14 months. Totally, 328 pregnant women were included: 149 in the telbivudine group and 179 in the control group. Baseline HBV DNA levels were similar in the 2 groups (7.43 vs 7.37 log₁₀ IU/mL, P = .711). At delivery, HBV DNA levels in the telbivudine and control groups were 3.80 and 7.26 log₁₀ IU/mL, respectively (P < .0001). Of the infants, 128 (85.9%) in the telbivudine group and 156 (87.2%) in the control group were followed up. No infant in the telbivudine group had chronic infection, while 2 (1.28%) infants in the control group did (P = .503). Three (2.34%) infants in the telbivudine group, but none in the control group, had severe congenital or developmental abnormalities (P = .090). The data indicate that telbivudine may block perinatal HBV transmission. However, larger studies are required to clarify whether anti-HBV therapy in pregnancy is associated with severe adverse effects in the foetuses and infants.

Minimization of hepatitis B infection among children in Jiangsu, China, 12years after integration of hepatitis B vaccine into the expanded program on immunization

BACKGROUND

China has integrated hepatitis B vaccine into the Expanded Program on Immunization since 2002. We aimed to survey the seroprevalence of and immunity to hepatitis B virus (HBV) in children born from 2002 to 2014 in Jiangsu, China.

METHODS

Totally 3442 children (M:F=2072:1370) at the age of 7months to 12years (5.5±3.6), from five cities and rural areas across Jiangsu province, were enrolled. Blood samples were measured for HBV markers by ELISA and quantitative microparticle enzyme immunoassay. HBV DNA was tested by real-time PCR and S region was amplified by nested PCR.

RESULTS

Twelve (0.35%) children were positive for hepatitis B surface antigen (HBsAg) and 34 (0.99%) were HBsAg negative and positive for antibody against hepatitis B core antigen (anti-HBc). Totally 2542 (73.85%) children had anti-HBs levels ⩾10mIU/ml and 535 (15.54%) with 2-9.9mIU/ml. All 12 HBsAg-positive children had detectable HBV DNA with a mean level of 6.1±1.7logIU/ml (3.3-8.1logIU/ml); 8 were genotype C and 4 were genotype B. No mutation was detected in the a determinant of HBsAg. HBV DNA was not detected in all the 34 children with positive anti-HBc and negative HBsAg.

CONCLUSION

HBsAg prevalence among children in Jiangsu born after the introduction of universal vaccination against hepatitis B has significantly decreased. No mutation of S gene is associated with vaccine failure in the cohort of children.

Naturally Occurring Surface Antigen Variants of Hepatitis B Virus in Tunisian Patients

In Tunisia, the prevalence of naturally occurring surface (S) gene variants of hepatitis B virus (HBV) has not been determined. In the present study, the prevalence of these variants was examined in terms of the clinical and viral state in a series of 99 Tunisian patients with HBV infection. The S genes were amplified and directly sequenced. Genotype D was predominant (98%), 40.4% isolates belonged to subgenotypes D7 and 1 to subgenotype D2. The most common subtype was ayw2 (95.9%). In total, 60.6% of the studied strains harbored S mutations. Several novel mutation patterns were detected. Interestingly, the presence of S mutations was significantly correlated with the D7 subgenotype, low HBV DNA and advancing age (≥35 years), and tended to be higher in liver cirrhosis than in chronic infection. The global prevalence of the major hydrophilic region variants was 12.1%, with substitution S143L/T as the most frequent (4%). Only 33.9% of S substitutions produced amino acid changes in the polymerase gene. In conclusion, a high prevalence of naturally occurring HBsAg variants was observed among Tunisian HBV carriers. Natural viral variability in a geographical region and duration of infection are among the major factors associated with the occurrence of S mutations.

Clinical and Virological Characteristics of Chronic Hepatitis B Patients with Coexistence of HBsAg and Anti-HBs

Coexistence of hepatitis B surface antigen (HBsAg) and antibody against HBsAg (anti-HBs) comprises an atypical serological profile in patients with chronic hepatitis B virus (HBV) infection. In this study, in total 94 patients with coexisting HBsAg and anti-HBs and 94 age- and sex-matched patients with positive HBsAg were characterized by quantitatively measuring HBsAg and HBV DNA, sequencing large S genes, and observing clinical features. Compared with common hepatitis B patients, the patients with coexisting HBsAg and anti-HBs had lower HBsAg and HBV DNA levels. These two groups had similar rate of pre-S deletion mutations. However, in patients with coexisting HBsAg and anti-HBs, more amino acid substitutions in the a determinant of S gene were observed in HBV genotype C, but not in genotype B. Fourteen patients with coexisting HBsAg and anti-HBs were followed up for an average of 15.5 months. There were no significant changes in the levels of HBsAg, anti-HBs, HBV DNA and ALT over the follow-up period. Compared with the baseline sequences, amino acid substitutions in the MHR of HBsAg occurred in 14.3% (2/14) patients. In conclusion, coexistence of HBsAg and anti-HBs may be associated with higher frequency of mutations in the a determinant of HBV genotype C.

Occult hepatitis B virus infection with positive hepatitis B e antigen

BACKGROUND

Hepatitis B e antigen (HBeAg) is a marker to indicate active replication of hepatitis B virus (HBV). Occult HBV infection (OBI), referred to persistence of HBV DNA in serum and/or liver without detectable serum hepatitis B surface (HBsAg), usually has low HBV DNA levels. The presence of HBeAg in OBI is unusual.

METHODS

We report 2 patients who presented negative for HBsAg but positive for HBeAg and HBV DNA. HBV markers were quantified in the longitudinal sera in a period of 1-2years. The HBV DNA sequences were analyzed in 2 patients' sera and 1 patient's liver.

RESULTS

Both patients were also positive for total anti-HBs and anti-HBc but negative for anti-HBe and anti-HBc IgM. HBV DNA levels were 234-567IU/ml in case 1 and 42-1130IU/ml in case 2. The alignment analysis of the S gene showed that HBV in both patients was genotype C, serotype adr. Cloning analysis of the a determinant of HBsAg showed that the immune escape mutants were predominant in both patients over the follow-up period. The HBV had double mutations (A1762T and G1764A) in the basal core promoter but had no mutation in the pre C/C gene in both patients.

CONCLUSIONS

The patients with negative HBsAg but positive HBeAg may represent a unique type of OBI. Test for HBeAg would be critical to identifying such type of OBI.

A novel nucleotide insertion in S gene of hepatitis B virus in a chronic carrier

Hepatitis B virus DNA was extracted from serum of a chronic carrier and polymerase chain reaction was performed on S gene. Direct sequencing showed a variant HBsAg with additional 4-amino acid insertion, and clone sequencing confirmed the mixture of variant HBsAg and wildtype HBsAg. Of 16 clones with 12-nucleotide insertion, 15 clones had identical AGAACAACACAA insertion between nucleotide 494 and nucleotide 495, and one clone had GGAACAACTCAA insertion in the same position plus 3-nucleotide deletion from nucleotide 491 to nucleotide 493. S114T, C121Y, T126S/A, Q129K, G130R, T131N, M133T, G145R, N146D substitution and premature stop codon were also found in those clones. However, the origin of HBV with 4-amino acid insertion in HBsAg was unclear.